1. Field of the Invention
The present invention relates to a flame-retardant biodegradable material and a manufacturing method thereof, a flame-retardant biodegradable polymeric composition, and a molded product and a method of disposal thereof.
2. Description of the Related Art
Under the concept that “the 21st century is an age of the environment”, a variety of environmental techniques have been investigated and proposed in order to build up circulation-type communities and as one of such techniques, biodegradable polymers have attracted attention.
The biodegradable polymers are polymers which can be theoretically decomposed into water and carbon dioxide units by microorganisms existing in soil or water or hydrolysis and are materials which are expected to have a high effect on reduction in industrial waste and saving in petroleum resources.
On the other hand, the biodegradable polymers in general have defects in mechanical strength and heat resistance. In order to overcome these defects, a technique to add a natural filler such as mica has been proposed (see JP-A-2002-173583)
In some cases where the biodegradable polymers are used as molding materials, the biodegradable polymers are expected to have flame resistance in addition to the above-described mechanical strength and heat resistance. However, any practical method for affording the flame resistance to the biodegradable polymers has not been established yet.
One of the reasons that make it difficult to afford the flame resistance to the biodegradable polymers is that flame retardant additives hitherto used for materials other than the biodegradable polymers can not be used for the biodegradable polymers. For example, phosphoric ester-series flame retardant additives themselves show high hydrolytic action and in addition, the biodegradable polymers promote hydrolysis of the flame retardant additives to make it impossible to secure sufficient flame resistance. Furthermore, hydrolyzates of the flame retardant additives cause the degradable polymers to deteriorate under the ordinary conditions of use. Although halogen-containing polymer-series flame retardant additives are known as other flame retardant additives, blends of the additives with the biodegradable polymers makes it impossible to say that such materials have biodegradability as a whole and to become a fundamental solution.